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Morita Shogi 64 checksum fixer
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#include <stdio.h> | |
unsigned int checksum(unsigned char *data, int length) { | |
unsigned char bVar1; | |
unsigned int uVar2; | |
int iVar3; | |
uVar2 = 0xffff; | |
bVar1 = *data; | |
while(1) { | |
data = data + 1; | |
iVar3 = 0; | |
uVar2 = (unsigned int)bVar1 << 8 ^ uVar2; | |
do { | |
if ((uVar2 & 0x8000) == 0) { | |
uVar2 = uVar2 << 1; | |
} | |
else { | |
uVar2 = uVar2 << 1 ^ 0x1021; | |
} | |
if ((uVar2 & 0x8000) == 0) { | |
uVar2 = (uVar2 & 0xffff) << 1; | |
} | |
else { | |
uVar2 = (uVar2 & 0xffff) << 1 ^ 0x1021; | |
} | |
if ((uVar2 & 0x8000) == 0) { | |
uVar2 = (uVar2 & 0xffff) << 1; | |
} | |
else { | |
uVar2 = (uVar2 & 0xffff) << 1 ^ 0x1021; | |
} | |
if ((uVar2 & 0x8000) == 0) { | |
uVar2 = (uVar2 & 0xffff) << 1; | |
} | |
else { | |
uVar2 = (uVar2 & 0xffff) << 1 ^ 0x1021; | |
} | |
uVar2 = uVar2 & 0xffff; | |
iVar3 = iVar3 + 4; | |
} while (iVar3 != 8); | |
length -= 1; | |
if (length == 0) break; | |
bVar1 = *data; | |
} | |
return ~uVar2 & 0xffff; | |
} | |
int main(int argc, char **argv) { | |
char save[0x200]; | |
if(argc < 2) return 1; | |
printf("%s\n", argv[1]); | |
FILE *f = fopen(argv[1], "rb"); | |
if(!f) return 1; | |
if(fread(save, 0x100, 2, f) != 2) return 1; | |
unsigned short c1 = checksum(save, 0xef); | |
unsigned short c2 = checksum(save + 0x100, 0xef); | |
printf("%04x\n%04x\n", c1, c2); | |
fclose(f); | |
return 0; | |
} |
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